Yes they are exploited simply because the people who are watching television want to see interesting things like this, and when the public is interested it means that the television programs will make a lot of money. These twins that are shown on tv also make a lot of money.
The public aren't interested in watching these awful reality shows because they have relevant cultural or social commentary to make. They're watching for the two-headed freak stumbling around the garden. If the shows were not exploitative in nature, they'd spend more time on post surgical separation stories of these twins.
To some people it may seem that conjoined twins, featured in reality television programs, are exploited. However, this is the reality of TV. We could say anyone who shows up in any given program is directly being exploited for entertainment purposes. There are benefits to being in these shows, namely monetary, regardless of the format they show up in.
It seems very sad to me to have such a thing as conjoined twins that have not been separated. However, reality tv does its job by exploiting various groups and yet rewarding them by paying them money and giving them fame. If these people are being well compensated and gain some popularity, then they are probably not considering themselves to be exploited.
If the funds of the reality show featuring conjoined twins is going toward their bills, then no I do not believe that they are being exploited. Conjoined twins have a lot medical bills in which their parents cannot afford and this show may help the family out financially and bring attention to issues that surround conjoined twins.